I've had that happen a few times. What your doing is just about all you can do. Sometimes if they don't have enough calcium, with a combination of growth, that happens. It may take a few weeks-months before your snail is back to normal. I love my snails and when they breed it gets me excited! I have mostly black mystery snails, along with a few yellow and blues. Hope all goes well!

And if the eggs seem to be getting dry, mist them once a day.